Brief treatment of nocadozole-arrested, metaphase cells with high levels of staurosporine causes a decondensation of the chromosomes and subsequent reinitiation of DNA synthesis leading to the emergence of the cells with a higher ploidy level. The histone composition of the treated cells also changes from that of mitotic cells to the composition of early S phase cells. It is speculated that this effect is in some way staurosporine-related and the result of the inhibition of M phase kinases or the induction of activity by phosphatases. Flow cytometry is being used to investigate the temporal induction of ploidy following treatment and for sorting of viable sorting of tetraploid cells determine if that are capable of dividing or if they continue to enter a higher ploidy level.